Cartridge stop for machine guns



NOV. 9, 1937. K, TURNBULL 2,098,264

CARTRIDGE STOP FOR MACHINE GUNS Filed April 28, 1937 Invent 1:? Norman K -Turnhull EJ WW w Z Attorney Patented Nov. 9, 1937 UNITED STATES PATENT OFFICE 4 Claims.

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

The subject of this invention is a cartridge stop for machine guns.

In the operation of machine guns the correct positioning of the cartridges for presentation to the breech bolt eliminates malfunctions due to improper feeding.

The purpose of this invention is to provide a simple and inexpensive stop member which will hold the cartridge against vertical displacement and which will have a surface positioned to engage the front edge of a cartridge case and prevent its forward displacement when struck by the extractor.

To these and other ends, the invention con- 20 sists in the construction, arrangement and combination of elements described hereinafter and pointed out in the claims forming a part of this specification.

A practical embodiment of the invention is illustrated in the accompanying drawing, wherein:

Fig. 1 is a plan view of a cartridge feedway of a gun, parts being removed to show the improved stop member.

Fig. 2 is a view in side elevation.

Fig. 3 is a perspective view.

Fig. 4 is a view in rear elevation of the stop member.

Referring to the drawing by characters of reference there is shown a portion of a machine gun of the Browning type comprising a receiver casing 5 having a transversely disposed channel or feedway 6 for passage of an ammunition belt 1. The floor 8 of the feedway includes an elevated front portion 9 for supporting the front end of 40 a cartridge case It] which is carried by the belt. The gun includes an axially movable breech bolt H which is provided withan extractor l2 for withdrawing a cartridge from the belt and which serves in a well known manner to cause actuation of a feed slide (not shown) which moves the belt through the feedway.

A block l3 inserted in the front part of the feedway at one side thereof and resting on the 50 floor 9 is secured to the receiver casing 5 in any convenient manner, specifically by a screw M. The inside wall of the block is formed with a partially cylindrical groove [5 extending longitudinally of the gun and adapted to receive the bullet is of the cartridge and thereby stop the cartridge in the correct position for withdrawal from the belt by the extractor. The upper portion of the block above the groove is extended to provide a lip I! which overlies the bullet and holds it against vertical displacement.

In the original gun, the cartridge is moved longitudinally into the proper position for extraction by means of a bunter plate l8 secured in place across the front end of the feedway and adapted to be engaged by the nose of the bullet as the cartridge moves through the feedway. As the breech bolt arrives in battery the extractor is obliged to ride over the base of the cartridge before it can engage the rim. This blow of the extractor causes the cartridge to move forwardly out of reach if the cartridge is of insumcient length to be held by the bunter plate or if the cartridge case can telescope on the bullet because of a damaged neck or one that fails to hold the bullet sufficiently tight.

In order to overcome this difiiculty the block is so arranged that the rear face l9 presents the marginal portion 20 defining the groove in a position to engage the front end of the cartridge case and prevent it from being driven forwardly by the extractor. This face therefore determines the proper position of the cartridge for extraction.

I claim:

1. In an automatic firearm, a receiver casing having a transverse cartridge feedway, a block in the front end of the feedway and at one side thereof, said block formed with a partially cylindrical groove disposed longitudinally of the gun, the upper portion of the block above the groove extended to provide a lip, and the block being so positioned that the portion of its rear face marginally defining the groove Will be engaged by the front face of a cartridge case that is positioned for extraction from the feedway.

2. In an automatic firearm, a receiver casing having a transverse cartridge feedway, a block in the front end of the feedway at one side thereof and forming a cartridge stop, a lip provided on the block and extending longitudinally of the gun to prevent tilting of a cartridge, and said block arranged so that its rear face is positioned to engage the front end of a cartridge case.

3. In an automatic firearm, a receiver casing having a transverse cartridge feedway, a block in the front end of the feedway at one side thereof and forming a cartridge stop, a lip provided on the block and extending longitudinally of the gun to preventtilting of a cartridge.

4. In an automatic firearm, a receiver casing having a transverse cartridge feedway, a block in the front end of the feedway at one side thereof and forming a cartridge stop, and said block arranged so that its rear face is positioned to engage the front end of a cartridge case.

NORMAN K. TURNBULL. 

